1. OASys Correlation parameter and Zero field run analysis summary Before the master thesis report OASys Correlation parameter and Zero field run analysis summary Rikkyo University Murata-lab Kentaro Watanabe 1

2. Optical Alignment System station1station3station2 The OASys is a composed of light sources on the station 1 which are distributed by the optic fiber from a halogen light balb, a convex lenes on the station 2, and a CCD camera at on the station 3. A combination of the light source, the lens and the camera is called as “A single line of the monitor”. There are seven “single lines” on the edge of the octant structure, therefore 7 × 8 = 56 in total for one muon arm. 56 OASYS cameras by each arm. total 112 cameras

3. How much the size of sagitta from W this study motivetion: The single muon spectrum is dominant with the origin of W in Pt 20 〜 40GeV. Then, the muon’s sagitta size is how much ? I want to know this value. According to front page,The magnetic field intensity is along a line at 15 degrees from the beam axis is 0.75 Tesla-meters(@South). 0.72 Tesla-meters(@North) Magnetic field the muon is flyting 15 degrees

4. How much the size of sagitta from W Using that information, I have calculated the size of sagitta with following formula. In here, I supposed the muon along a line at 15 degrees from the beam axis. ※ In here, Pt is defined as the right angle component across the magnetic field. In phnx coordinates, this Pt is Pz. Not using this approximation, I did cross check this value.

5. muon momentumSouthNorth θ = 15 degreesradius of curvaturesagittaradius of curvaturesagitta P [GeV]Pz [GeV]Pt [GeV]ρ [m]Δs [mm]ρ [m]Δs [mm] 10.4102.7138.08.1191.710.4 15.5154.0207.15.4287.67.0 20.7205.4276.14.1383.45.2 25.9256.7345.13.3479.34.2 31.1308.0414.12.7575.23.5 41.44010.7552.12.0766.92.6 46.64512.1621.21.8862.72.3 51.85013.4690.21.6958.62.1 62.16016.1828.21.41150.31.7 72.57018.8966.31.21342.01.5 82.88021.41104.31.01533.71.3 93.29024.11242.30.91725.51.2 103.510026.81380.40.81917.21.0 113.911029.51518.40.72108.90.9 124.212032.21656.40.72300.60.9 134.613034.81794.50.62492.30.8 144.914037.51932.50.62684.00.7 155.315040.22070.60.52875.80.7 The calculation result is following table. It shows the sagitta of muon along a line at 15 degrees from the beam axis. Over 20GeV pt muon is almost 5mm curved in Muon Tracker. How much the sagitta from W W signal The size of sagitta from W is about 500 μ m 〜 1mm. ( the muon along a line 15 degrees ) This value is consistent with simulation’s value ?? And I want to know the impact of miss alignment for W

6. Optical Alignment System The OASYS consists of a light source at station 1, a convex lens at station 2, and a CCD camera at station3. When an individual station moves, the image on the CCD camera moves reflecting the station movement. By observing the position of the light spot on the image of the CCD camera, we can monitor each station’s movement. ① ⑤ ④ ③ ② ⑦ ⑥ half octant We use a halogen lamp and optical fiber as a light source for the OASYS. Optical fibers guide light from the halogen lamp It is attached on the edge of station1. Seven CCD cameras have been set up to each octant as in a diagram. Horizon direction and vertical direction are defined as x and y. The plane of the CCD camera are mounted almost parallel to the camber plane, the OASys can measure the movement on the X-Y plane, which is direction of the track bending.

7. Optical Alignment System CCD cameras used in OASYS have 8.8mm(768(horizontal) pixel) ×6.6mm (498(vertical) pixel) acceptance. Size of 1 pixel segment is 11.0 μ m(horizontal) × 13.0 μ m(vertical). However, when the video signal is read in a PCI capture board, only 640 pixel (horizontal) × 480 pixel (vertical) range is selected. capture raw data image The results of measurement are peak position distributions for 1000 samples obtained within 30 minutes. The typical sharp image and the typical broad image are displayed. The measured resolution is 1.4 μ m for sharp image, and 3.1 μ m for the broad image. projection X Resolution for the CCD camera projection Y The typical sharp image The typical brod image resolution is 1.4 μ m resolution is 3.1 μ m Projection Method 1. Make 640 × 480 sized 2-dimension array from CCD image. An element means brightness on the pixel. 2. Search for a peak position of the image array, and make projection around peak with 100 pixel range. 3. The method of “projection” is defined as the sum of pixels in the effective range.

8. Normalize vertical (first day opsition) Range : -15[pixel] to 15[pixel], Horaizontal Range : 2010/1/10~2010/4/20 Displacement Sample Picture 50 μ m South arm camera 50 direction Y South arm camera 50 direction X not good peak this area not entry fitting the focus of some OASYS cameras is not good. These camera’s projection peak can not gauss fit, therefor the center of peak is cut off contribution of fitting. 70 μ m Optical Alignment System

9. North Arm South Arm All camera X direction Normalize vertical (first day opsition) Range : -15[pixel] to 15[pixel], Horaizontal Range : 2010/1/10~2010/4/20 All camera X direction 12 camera broken 3 camera broken

10. OASys Correlation Parameter 10 OASys は Muon tracking chamber と一体であり、その OASys のシグナルは chamber の動きを完全にトレースしているものと考えたい。しかし、実際には OASys 自身の系で独立なパラメターが存在するため、 OASys の画像には chamber の動き以外の要因が混在しているだろう。というのが現状の理解であ る。

11. 11 温度 温度に相関がある事は確かである。現時点で最も OASys の存在意義を脅かす 存在。 Muon Magnet の発熱だけによるチェンバーの膨張 / 収縮は簡単なモデルで 表せないようにみえる。詳細記述は intoro 以降。 湿度 湿度が OASys のシグナルに影響を及ぼすとすれば、空気内の保湿量による屈 折率の変化などが考えられる。しかし、現時点で 20% 程度の湿度変化では OASys のシグナルに変化は見られない事を池田解析により確認。 磁場 Muon Magnet の on/off により、 OASys が示す各々のカメラの輝度は変化する 事は確実である。そして、その方向は磁場の方向と一致する動径方向である事 も確認されている。 MuTr チェンバーの動径方向への動きが支配的であり、大き く動いたカメラで 100 μ m 程度動いているように見える。しかし、 MuTr チェン バーの動径方向の位置分解能は 300 μ m 程度し かないため 100 μ m 程度の動きな ら無視する事が出来る。そのため、磁場による MuTr チェンバーの動 きは無視 する事が出来ると言える。 その他の外力 重力： MuTr 自体の重み、１００８全体の沈降。 朝夕力：月の引力によるチェンバーの歪み、または地面の隆起沈降。

12. 12 根本的に OASys が表したチェンバーの動きというものが正しいのか正しくないのか という検証は OASys とは独立した系でチェンバーの動きを測定し、それとの整合性 を測る事で行う。 その各 Station の相対位置を探るもう１つの手段が Zero field run と呼ばれる、磁場を かけない状況下での muon の飛跡検出である。この状況下では全てのトラックは直 線となり、相対的なミスアライメントの量を推測出来る。ある期間での、このミス アライメントの変化量と OASys が示す所の変化分との相関性を見いだす事が現時点 での最重要課題である。 PHENIX Physics RUN zero field run 1st zero field run 2nd zero field run 3rd few months OASys data taking Re-Alignment warning!! OASYS の動き ＝ ゼロ磁場下でのミスアライメントの量 の変化 と言う事で、まずゼロ磁場での測定結果のまとめッ ス！！

13. Zero field 解析 Index 13 ・ Zero field run 解析原理 ・ Sagitta の定義と分布 ・ Sagitta 分布の考察と検証 – ハドロン decay の効果： cosmic による推察。 – muon の運動量依存性：多重散乱の simulation ・ Fitting function の最適化 ・ ミスアライメントの変化量算出 ・ OASys との相関

15. θ sagitta_x sagitta_y sagitta_w sagitta_r track point extarnal point Sagitta Point

16. External point error estimated track_z[0] track_z[1] track_z[2] track_x[0] track_x[1] external_x track_x[2]

17. what is the composition sample: south octant8 half2

18. 18 South Arm

19. 19 North Arm

20. South Arm Normalized

21. North Arm Normalized

22. この形は何から来てるの け？ 22 この形は何から来てるの け？

23. if this component is consisted from hadron decay, it will be disappeared in cosmic run. Run9 Zero Field Cosmic To make sure the idea that “2nd gaussian component is hadron decay” is true or not. I have checked the sagitta distribution of cosmic Run9 magnet off cosmic data.

24. Run9 Zero Field Cosmic Data select requirement ・ magnaet off : CMO CMI MMS MMN =0 ・ Partition : Big ・ Run Type : CALIBRATION ・ Trigger Config : Calibration ・ before beam :cosmic ・ trigger : MUIDLL1_N1D||S1D Enabled Run Number : 268521, 268543 〜 268552

25. Run9 Zero Field Cosmic South Arm event North Arm event South North half octant 1 half octant 2 The conclusion may be too early to say. However I got a look, 2nd gaissian effects have not disappeared. These results suggest that the idea of hadron decay is wrong. ← Octant 1 と４の count が少ないのは cosmic の特徴。

26. これが cosmic の sagitta distribution だぞ （ North ） 26

27. 27 これが cosmic の sagitta distribution だぞ（ South ）

28. 28 South Arm : 黒、３月。赤、５月。青、宇宙線。

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30. Muon momentum study motivation: I have to compere the different beam condition data. If the two data’s muon momentum distribution is change, the residual distribution will be change. Especially, if the ratio of low momentum spectrum increase at pp200GeV, the 2nd gaussian component will increase by hadron decay or multiple scattering effect. So, I have checked muon momentum distribution around Zero field run. zero field cosmic 1st zero field 2nd zero field pp500GeV pp200GeV March May January different beam condition

31. 衝突点で発生した粒子はまず NeosCone( 銅 ) と Central Magnet( 鉄 ) を通る。これら の吸収材による反応 長は ̃ 5 程度でこの時点でハドロンの数は 1/100 になる。また、 5 層の MuID には 1 層ごとに鉄が挟まっ ており、 μ 粒子が MuID の 5 層目まで到 達するには 2.5GeV/C の運動量が必要となる。 ( ← ハドロン吸収材を Run11 から導 入したから変わった？ ) 2.5GeV/c ← first layer 0 origin Muon ID trigger

32. Muon momentum study pp500GeV momentum [GeV] run condition under 10GeV 97.3% of ALL !! This spectrum is pp500GeV track associated muon momentum distribution (No track cut ). 500GeV (3104228/3187765) 97.3%

33. momentum [GeV] High pt spectrum seems to decrease than pp500GeV. However under 10GeV muon is 98.3%, high pt muon is not sensitive for the residual distribution. Muon momentum study pp200GeV run condition under 10GeV 98.3% of ALL !! 200GeV (961325/945105) 98.3%

34. Muon momentum study summary pp200GeV pp500GeV momentum [GeV] The residual distribution is based on under 10 GeV muon. The spectrum is same in pp200GeV and pp500GeV. It means the residual from different beam can be compered. And the different of beam is not sensitive 2nd gaussian. pp200GeV pp500GeV 1/momentum [/GeV] Normalized ( 〜 10GeV) 1/p Normalized log scale 1GeV 0.2GeV

35. simulation study From zero field cosmic study, we make sure second gaussian component is not based on hadron decay. So, we guess that component will be based on the effect of multiple scattering another momentum. After the last meeting, Oide-san gave me simple multiple scattering root macro. I modified that macro to near real condition. Fist Step : Air volume contribution (fix muon momentum) At first I assumed if 2.0 GeV muon go through between St1 to St3. Then muon is affected by the effect of multiple scattering from air volume. I want to know the final position (St3) is how much spread by that effect. 2GeV muon st1 st3

36. collision external point stub point st3 sagitta stub point st2 stub point st1 stub point st3 external point つまり、この間での多重散乱 の効果を考慮すればよい。 この間での多重散乱の効果は sagitta に影響しない。 station3 での sagitta を考慮する際の multiple scattering の効果

37. calculation by hand The multiple scattering is roughly Gaussian for small deflection angles, the projected angular distribution, with a width given by The projected y direction distribution is given by @ South station2 〜 station3 moun momentum : 2GeV x : 160cm air radiation length : 37g ・ cm^-2 air density : →σ = 469 μ m

38. the result of simulation 2GeV muon The cause of fixed momentum 2Gev, it can be fit with single gaussian. This simulation consistent with hand calculation.

39. different momentum distribution 1GeV fixed RMS: 939 μ m 2GeV fixed RMS: 470 μ m 5GeV fixed RMS: 188 μ m 10GeV fixed RMS: 94 μ m

40. different momentum contribution The second gaussian component is appeared !!!

41. Fit 2gaussian simulation data momentum 1 〜 10GeV RChiS= 1.1019

42. typical raw data South 0ct1-1 pp500GeV-Zerof Compere with raw data The Shape of simulation distribution is the same with typical raw data. However, the amplitude is difference…..

43. A few octant have asymmetry distribution. It is not first priority to find out this asymmetry source. However, I was able to find out that source by simple correlation study. So, today I would like to talk about this study.

48. This plot is typical sagitta distribution of φ direction. Now, I think this distribution has 3 main component and it is fit with 2gaussian+pol0 function. ( 1st gaus = true signal, 2nd gaus = hadron decay mode, pol0 = noise offset ) However, the problem is 2nd gaussian component is not stable between Run9 march to Run9 may zero filed run. What is this source? The idea of hadron decay mode is true or not. gaussian pol0 Fitting function study Fitting function study

50. The change of Second gaussian component 上記の通り、２つのガウシアンと pol0 でフィッティングを行うと３月のデータと ５月のデータで第２ガウシアンの ratio が変化しているように見受けられる。特に ５月のデータでは、その量が総じて減っている。この理由を考察する事で今まで ハドロンの decay として扱っていた２つ目の component に対して正確に ID する事が 今回の study の目的である。 Run9 March South Oct8 half1 Rchis : 1.82 Run9 May South Oct8 half1 Rchis : 3.07 単純に Fit が上手く決まらないのが原因で第２ ガウシアンの要素が死んだと考えるものの sample 。 Run9 March Norh Oct3 half1 Rchis : 1.24 Run9 May Norh Oct3 half1 Rchis : 170 Fit は上手くいっていて本当に第２ガウシアンのス ペクトルの形が変化したのかもしれない。と思う もの。

51. RChis RChis 1.5 Number of events is over 1.0*10^4 by each octant. so that RChiS will be around 1±√N

52. Run9 March Sigma North: AVE 0.208 ±0.0013 [cm] South: AVE 0.146 ±0.0005 [cm]

53. Run9 May Sigma North: AVE 0.290 ±0.0023 [cm] South: AVE 0.176 ±0.0013 [cm]

54. Run9 May mean @south

55. Run9 May mean @north

58. 1 2 3 4 5 6 7 8 Run9 South March mean position direction ?

59. 1 2 3 4 5 6 7 8 Run9 North March mean position direction ?

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